Conventionally, to observe the vascular structure by conducting angiography imaging, X-ray diagnostic apparatus employ digital subtraction angiography (DSA) imaging. DSA imaging is an imaging method in which an X-ray image (hereinafter, referred to as the “mask image” as appropriate) in a state where the contrast media is not injected and an X-ray image (hereinafter, referred to as the “contrast image” as appropriate) in a state where the contrast media is injected are acquired and subtraction is conducted on the images so that a DSA image is obtained in which only a blood vessel is extracted.
Here, with regard to the region where blood vessels are overlapped on the above-described DSA image, although the blood vessel that is firstly contrast-enhanced due to the contrast media may be observed, it is sometimes difficult to observe the subsequently contrast-enhanced blood vessel. For example, if the overlapped blood vessel is contrast-enhanced before the contrast media is removed from the firstly contrast-enhanced blood vessel, the difficulty arises in distinctively observing the subsequently contrast-enhanced blood vessel and the firstly contrast-enhanced blood vessel.
Therefore, according to conventional technologies, if blood vessels are overlapped on a DSA image, for example, a C-arm is moved to an angle such that the firstly contrast-enhanced blood vessel and the subsequently contrast-enhanced blood vessel are not overlapped, the contrast media is injected again, and a DSA image is obtained. Alternatively, for example, after the catheter is inserted from the firstly contrast-enhanced blood vessel to the periphery side, the contrast media is injected again, and a DSA image is obtained.